Related papers: Bounds on extra quark-lepton generations from prec…
Searches for charginos, neutralinos and sleptons at LEP2 centre-of-mass energies from 130 GeV to 189 GeV have been used to set lower limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles within the…
We update the bounds on fermions with electric charge $\epsilon e$ and mass $m_\epsilon$. For $m_\epsilon\lsim m_e$ we find $10^{-15}\lsim\epsilon<1$ is excluded by laboratory experiments, astrophysics and cosmology. For larger masses, the…
We analyse the impact of LHC and Tevatron Higgs data on the viability of the Standard Model with a sequential fourth generation (SM4), assuming Dirac neutrinos and a Higgs mass of 125 GeV. To this end we perform a combined fit to the signal…
It is a challenge to explain why neutrinos are so light compared to other leptons. Small neutrino masses can be explained if right-handed fermions propagate in large extra dimensions. Fermions propagating in the bulk would have implications…
Following previous works regarding electroweak precision tests in supersymmetry, we continue to explore their implications to the MSSM and NMSSM both of which are tightly constrained by the Higgs mass and its decay experiments at the LHC.…
We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least…
We use the LHC Higgs data to derive updated constraints on electroweak-scale sterile neutrinos that naturally occur in many low-scale seesaw extensions of the Standard Model to explain the neutrino masses. We also analyze the signal…
We investigate squark and gluino pair production at LHC(CMS) for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in $(n \geq 2)jets + E^{miss}_T + (m \geq leptons)$ events depends rather…
How light can a fermion be if it has unit electric charge? We revisit the lore that LEP robustly excludes charged fermions lighter than about 100 GeV. We review LEP chargino searches, and find them to exclude charged fermions lighter than…
If three right-handed neutrinos are added to the Standard Model, then, for the three known generations, there are six quarks and six leptons. It is then natural to assume that the symmetry considerations that have been applied to the quark…
The addition of gauge singlet fermions to the Standard Model Lagrangian renders the neutrinos massive and allows one to explain all that is experimentally known about neutrino masses and lepton mixing by varying the values of the Majorana…
Within the framework of a Beyond Standard Model (BSM) with a local $SU(3)$ family symmetry, we report an updated fit of parameters which account for the known spectrum of quarks and charged lepton masses and the quark mixing in a $4\times…
A new flipped $SU(3)_C\otimes SU(4)_L\otimes U(1)_X$ model without exotic electric charges is proposed. All the quarks families are arranged in the same representation while leptons generations are in different representations leading to a…
The most important hint of physics beyond the Standard Model (SM) from the 1995 precision electroweak data is that the most precisely measured quantities, the total, leptonic and hadronic decay widths of the $Z$ and the effective weak…
We study the possibility of generating tiny Dirac masses of neutrinos in Left-Right Symmetric Model (LRSM) without requiring the existence of any additional symmetries. The charged fermions acquire masses through a universal seesaw…
We derive limits on a class of new physics effects that are naturally present in grand unified theories based on extended gauge groups, and in particular in $E_6$ and $SO(10)$ models. We concentrate on $i$) the effects of the mixing of new…
We propose a new strategy to probe heavy neutrinos with non-universal fermion couplings at the Large Hadron Collider (LHC) using a novel production mechanism and machine-learning algorithms. Focusing on proton--proton collisions at…
Upper bounds on the CP asymmetry relevant for leptogenesis are reexamined and found weaker than in previous literature, both for hierarchical and for quasi-degenerate right-handed neutrinos. Successful leptogenesis implies the usual lower…
Phenomenological analysis to the R-parity violating supersymmetry with a vector-like extra generation is performed in detail. It is found that, via the trilinear couplings, the correct neutrino spectrum can be obtained. The Higgs mass rises…
The Standard Model (SM) with a light Higgs boson provides a very good description of the precision electroweak observable data coming from the LEP, SLD and Tevatron experiments. Most of the observables, with the notable exception of the…